Unusual Morphological and Behavioral Traits in Abrocoma (Rodentia: Abrocomidae) from Argentina

We report a series of unusual morphological and ecological observations for a specimen of Abrocoma vaccarum, a member of the South American caviomorph family, Abrocom idae. The specimen, collected in Mendoza Province, Argentina, has buccal epidermal den ticles, or false teeth, in the midline of the mouth and a tongue with a horny pad. The animal also seems to store a watery liquid subcutaneously around the cranium, perhaps enhancing the broad-headed appearance of the species. A. vacca rum inhabit fissures in rock cliff faces and form remarkable latrines that likely are highly persistent over time. These and other features indicate that this species is a highly unusual rock specialist.